It is known to engagingly attach a terminal to a wire conductor by a crimp to form an electrical connection.
Wire conductor/terminal crimps are common in wiring harnesses used in many industries, such as the automotive, trucking, and airline industries. Wiring harnesses provide the conduit for electrical signal transmission that support the operation of electrical devices in electrical systems in these industries. In the automotive industry, it is increasingly desirable to use lighter weight wire conductors that may assist to provide desired increased fuel economy for a vehicle. These lower mass aluminum wire conductors are often electrically connected to commercially available non-aluminum terminals. The wire conductor is electrically and mechanically connected to the terminal to form the electrical connection. When aluminum wire conductors are used in electrical applications, knurl patterns may assist to break up undesired aluminum oxides formed on the aluminum wire conductor that allow formation of an acceptable electrical connection of the wire conductor to the terminal. Aluminum oxides that are not broken-up when the electrical connection is formed may degrade the performance of the electrical connection such that transmission of an electrical signal through the wire conductor/terminal electrical connection is undesirably degraded or prohibited.
Another undesired characteristic that may degrade the electrical performance of the wire conductor/terminal crimp may be voids that form in the knurl pattern during formation of the crimp. Referring to prior art FIGS. 1 and 1A, a conventional knurl pattern contains knurl elements (1) that each have a recessed square pyramid-type shape that may contain voids (2) in the crimp (3) where portions of the aluminum lead (4) do not engage in the square pyramid-type recessions when the lead (4) is crimped to the terminal (5). When the knurl pattern is constructed, the recessed tips of the square pyramid-type knurl elements point in a direction away from the interior surface of the terminal. These undesirable voids (2) do not contain a portion of lead (4), and thus, cannot electrically connect the aluminum lead (4) with the terminal (5) in the crimp (3). Multiple voids prevent achievement of a desired maximum electrical and mechanical connection between the aluminum lead (4) and the terminal (5) as may be the case if, in contrast, the voids were filled with portions of the aluminum lead. Additionally, the surface area of the lead (4) in the local vicinity of the void may also contain aluminum oxides that are not broken up when the wire conductor/terminal electrical connection is formed. As aluminum wire conductor continues to gain popularity with vehicle manufacturers and aluminum oxides remain a prevailing problem that may prevent acceptable wire conductor/terminal electrical connections, it remains a very desirable goal to maximize the break-up of aluminum oxides while also further improving the electrical and the mechanical properties of the wire conductor/terminal or wire cable/terminal electrical connection over the service life of the vehicle.
Thus, what is needed is an electrical contact that overcomes the above mentioned shortcomings and includes a knurl pattern where each element in the knurl pattern has a shape and a shape orientation relative to a wire cable received in to the electrical contact that allows for a more complete break-up of aluminum oxides on a substantial portion of the lead of the wire cable while also providing an improved electrical and mechanical connection between the aluminum wire cable and the electrical contact.